Activity Limitation Stages Are Associated With Risk of Hospitalization Among Medicare Beneficiaries.

The study was observational, so it cannot show that activity limitation stages cause hospitalization. Unknown confounders could not be ruled out. Functional status was assessed annually and by self- or proxy-report, so changes within a year may have been missed and stage may have been misclassified. The sample excluded beneficiaries in managed care programs and people living in long-term care, so it does not apply to all older Medicare beneficiaries. Attrition was large: 9,447 beneficiaries were included at baseline, but 6,424 and 4,516 were included in the second and third years. The later recurrent hospitalization analyses had smaller numbers, especially 149 fourth hospitalizations, so null findings for later hospitalizations need caution.

The authors reported no personal conflicts of interest and no disclosures beyond the funding source. They also stated that no party with a direct interest in the results has or will confer a benefit on them or any organization with which they are associated.

Do not read the higher hazard ratios as proof that activity limitation stages cause hospitalization or that treating these stages will prevent it. This was an observational survey analysis, and the authors could not rule out unknown confounders. The association was for first hospitalization only, not for later hospitalizations.